Expanding Universe: Concepts and Discoveries

Questions and Answers

What discovery made by Edwin Hubble contributed to the understanding of an expanding universe?

Redshift in spectral lines (correct)

Static positions of stars

Constant density of galaxies

Blue shift in spectral lines

What is the approximate age of the universe?

13.8 billion years (correct)

10.5 billion years

14.5 billion years

15.2 billion years

What is the density of the universe described in the content?

4.5 x 10-31 g/cm3 (correct)

3.3 x 10-31 g/cm3

9.8 x 10-31 g/cm3

1.2 x 10-31 g/cm3

Which narrative describes the creation of the universe by a god in Central Africa?

The myth of Mbombo (Bumba) Signup and view all the answers

What is suggested about the universe in relation to its appearance on a large scale?

It is homogeneous and isotropic Signup and view all the answers

What does the term 'redshift' signify in the context of astronomy?

Spectral lines shift towards lower frequencies Signup and view all the answers

In which mythology does the universe arise from an infinite sea?

Ancient Egyptian mythology Signup and view all the answers

How do the positions of absorption lines for helium from the Sun compare to those from a distant star?

They are shifted toward the red end Signup and view all the answers

Study Notes

Structure of the Universe

The universe shows clumpiness at smaller scales but is homogeneous and isotropic on a larger scale.
Estimated age of the universe is 13.8 billion years.
Diameter is at least 91 billion light-years, potentially infinite (1 light-year = 9.4607 × 10^12 km).
Average density of the universe is 4.5 x 10^-31 g/cm³.

Expanding Universe

Discovery of the redshift by Edwin Hubble in 1929 indicated galaxies are moving away from each other.
Hubble's observations confirmed predictions made by Einstein's Theory of General Relativity.
Redshift is the displacement of spectral lines of starlight towards red wavelengths, suggesting celestial bodies are receding.
Evidence shows absorption lines for helium from the Sun are shifted to red compared to distant stars.
This contradicted earlier beliefs of a static and unchanging universe.

Origin of the Universe

The universe encompasses all space-time, matter, energy, solar systems, stars, galaxies, and intergalactic content.
Various cultural narratives reflect human attempts to explain the universe's origin through mythology and religion.

Cultural Myths

Ancient Egyptians believed in multiple gods and that the world emerged from an infinite sea at sunrise.
The Kuba people of Central Africa narrate creation by the god Mbombo, who vomited the stars, sun, and moon after feeling pain.
In India, the sacrifice of Purusha, a primal man, leads to the creation of the sky, earth, sun, and moon from his body.
Monotheistic religions, including Judaism, Christianity, and Islam, assert a supreme being created the universe and all life.

Description

Explore the fascinating concepts of the expanding universe, including its clumpiness and homogeneity. This quiz covers significant discoveries such as Edwin Hubble's announcement of redshift and the estimated age and size of the universe. Test your understanding of the key principles that describe our cosmos.